The following is provided as background information only. Nothing in this section is intended to be, nor should it be construed as, prior art to the subject invention.
Battery-powered devices have become ubiquitous in present day life. Anything from heart pacemakers to automobiles can be powered by batteries. While battery power removes the previously limiting tether to a stationary power source, battery power does come with inherent limitations. Their useful lifespan is limited and, as is quite well known to virtually everyone, batteries have a tendency to die at the most inopportune moments. Stories abound relating to hikers whose GPS's quit during a trek and about cell phones that give out when a person has had an accident or is stranded somewhere for some reason or another. In addition, although great stride have been made, batteries still weigh a significant amount, in particular in situations where back-up batteries must be carried to ensure continuous operation of crucial devices. Military uses, of course, come immediately to mind. It has been estimated that the weight of batteries alone that current day combat troops carry into battle can account for upwards of 30% of the total weight of the gear being carried. The effort required to carry such heavy loads have been shown to have marked detrimental effect on soldiers' ability to perform when called upon to do so. The problem is so serious that DARPA attempted to assuage the problem by issuing combat boots with piezoelectric devices in the sole of the boot, the idea being to generate a watt or two from the simple expedient of walking, which soldiers do a lot. The boots, however, proved so impractical and uncomfortable due to the added expenditure of energy to operate the device that the project was abandoned.
What is needed is a reliable, very light weight, virtually fail-safe device for powering devices as a complete substitute for batteries or as a extender of battery life to reduce or eliminate the need for backup batteries. The present invention provides such a device and method.